1. Field of the Invention
The present invention relates to an inkjet recording head to be mounted on an inkjet recording apparatus used in inkjet recording systems, and also relates to a method for manufacturing the inkjet recording head.
2. Description of the Related Art
An inkjet recording head (hereinafter referred to as a recording head) includes a substrate having at least a plurality of discharge ports, a flow path communicating with the discharge ports, a supply port configured to supply ink to the flow path, and an energy generating element to impart discharge energy to the ink in the flow path. The inkjet recording head further includes a support member to support the substrate and an ink-supply-path forming member to supply ink to the substrate. In the substrate, a Si (silicon) substrate is normally used. The ink-supply-path forming member is made of plastic, for example.
Heretofore, the inkjet recording apparatus described above has had a problem that the recording element substrate would suffer warpage or distortion due to an increase in stress at the joint interface caused by a difference in linear expansion coefficient between the ink supply member containing the liquid and the recording element substrate including the energy generating element for discharging a liquid from the discharge ports.
This phenomenon is described with reference to FIG. 4. FIG. 4 illustrates the inkjet recording head including a recording element substrate 41 and an ink supply member 42. The recording element substrate 41 is made of a material with a linear expansion coefficient of not more than 5 ppm, whereas the ink supply member 42 is made of a material with a higher linear expansion coefficient of 20 ppm or more. Accordingly, there is a difference in linear expansion coefficient between the recording element substrate 41 and the ink supply member 42. The recording element substrate 41 is fixed to the ink supply member 42 with an adhesive.
When printing is carried out by an inkjet recording head according to the configuration illustrated in FIG. 4, due to temperature rise during printing, thermal stress occurs at the joint interface between the recording element substrate 41 and the ink supply member 42, which gives rise to a deformation of the recording element substrate 41 and has a bad influence on print quality.
As a way of solving the above problem, U.S. Pat. No. 6,257,703 describes a configuration in which a support member having the linear expansion coefficient equal to the recording element substrate, is located between the recording element substrate and the ink supply member.
However, recently, there is increasing requirement that recorded images have high resolutions and the effect on images stemming from a deformation of the recording element substrate should be minimized. Therefore, it has become necessary to further reduce the stress caused by a difference in linear expansion coefficient between the ink supply member and the substrate.